Hydrological Processes最新文献

{"title":"Environmental and Spatial Variables Influencing Contaminants of Emerging Concern in Watersheds Across Central NY","authors":"Ruta Basijokaite,&nbsp;Shiru Wang,&nbsp;Teng Zeng,&nbsp;Christa Kelleher","doi":"10.1002/hyp.70623","DOIUrl":"https://doi.org/10.1002/hyp.70623","url":null,"abstract":"<p>Monitoring studies have identified the occurrence of hundreds of contaminants of emerging concern (CECs) throughout water, sediments, and biota. Despite their ubiquitous presence, relatively few studies explore how environment and land use affect CEC occurrence. In this work, we performed temporal sampling across proximal watersheds, which provided a unique opportunity to study influences on regional CEC presence and to identify overarching patterns in CEC behaviour. We collected grab samples in twenty mixed-use watersheds around central New York throughout 2018 and 2019 across diverse hydrologic and environmental conditions. Samples were analysed using liquid chromatography-high resolution mass spectrometry and quantified with reference standards producing CEC concentrations. A total of 79 CECs were identified; their concentrations were analysed using correlation analysis and Ordinary Least Square (OLS) modelling to assess relationships between their concentrations, land use, and environmental factors. Our results show that in addition to varying water quality levels among different sites, CEC behaviour is highly variable among compounds. In addition, we show that urban and agricultural land cover can be highly useful in predicting the number and concentration of detected compounds. These findings can be used to support data-driven CEC models as well as inform future mitigation and monitoring strategies.</p>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"40 7","pages":""},"PeriodicalIF":3.1,"publicationDate":"2026-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hyp.70623","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148386494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Climate Sensitivity of Humid Boreal Forest Stream Water Sourcing Informed by Variation in Air-Stream Temperature Regression","authors":"Helia Kamel,&nbsp;Karen Prestegaard,&nbsp;Susan E. Ziegler","doi":"10.1002/hyp.70607","DOIUrl":"https://doi.org/10.1002/hyp.70607","url":null,"abstract":"<div>\u0000 \u0000 <p>Boreal landscapes are undergoing rapid climate change and are predicted to experience large increases in terrestrial carbon mobilization. The fate of this carbon, critical for predicting terrestrial-to-aquatic carbon fluxes and landscape carbon balance, is influenced by hydrological pathways regulating water sources and stream temperature in headwater systems. To assess hydrological responses to climate variability, we analysed air–stream temperature (AST) regressions for nine boreal headwater catchments across three regions of a north–south climate transect in eastern Canada, using ice-free period data spanning 5–7 years. Small, steep catchments in the warmest region exhibited low AST slopes and high intercepts, consistent with greater groundwater contributions and thermal buffering. In contrast, higher AST slopes and lower intercepts in larger, low-relief catchments in colder regions indicated stronger atmospheric coupling and greater influence of near-surface flowpaths. Although spatial variation in slope_AST and intercept_AST was associated with basin area and steepness, interannual variability revealed climate controls on stream water sources and thermal responses that depended on geomorphic setting. In small, steep catchments, greater autumn precipitation prior to peak discharge was associated with higher slope_AST and lower intercept_AST, consistent with enhanced air–stream coupling and activation of shallow flowpaths. In contrast, snowpack duration influenced AST regressions in larger, low-relief catchments of colder regions. Longer snowpack periods decreased intercept_AST, whereas reduced snowpack enhanced thermal sensitivity to ice-free air temperature. These results demonstrate that thermal and hydrological responses to climate variability depend on geomorphic structure and baseline stream thermal behaviour. Shallow flowpath contributions in thermally buffered small, steep headwaters appear sensitive to evapotranspiration and precipitation, whereas larger, low-relief headwaters may be more sensitive to changing snowpacks. Headwater AST regressions indicate coupled thermal and hydrological sensitivity, supporting predictions of hydrological and carbon fluxes in boreal landscapes.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"40 7","pages":""},"PeriodicalIF":3.1,"publicationDate":"2026-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148386495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detecting Hidden Environmental Flow Alteration in Groundwater-Irrigated Basins","authors":"Salam A. Abbas,&nbsp;Gerardo Castellanos-Osorio,&nbsp;Jeremy T. White,&nbsp;Javier Senent-Aparicio,&nbsp;Ryan T. Bailey","doi":"10.1002/hyp.70626","DOIUrl":"https://doi.org/10.1002/hyp.70626","url":null,"abstract":"<div>\u0000 \u0000 <p>Effective and balanced management of economic and environmental concerns in groundwater-irrigated basins is a world-wide challenge. Environmental flow modification is increasingly influenced by groundwater-supported irrigation in these heavily irrigated regions, yet the ability to rigorously quantify how groundwater-based irrigation influences ecological surface-water flows remains limited, leaving resource managers with difficult and opaque decisions regarding resource allocation. This work presents a generic and generalised framework to programmatically evaluate how groundwater use for irrigation has altered surface-water flow characteristics by using an integrated surface-subsurface modelling system paired with rigorous ensemble-based data assimilation. As an example, we demonstrate the mechanisms linking groundwater dynamics to environmental flow alteration in groundwater-dependent river systems, utilising the Mississippi Alluvial Plain (MAP), USA, as a representative study. Specifically, a coupled SWAT+<i>gwflow</i> model was applied across six HUC-8 watersheds and calibrated using an iterative ensemble smoother, incorporating both monthly streamflow and groundwater head observations. Model performance was evaluated using multiple hydrologic metrics and independent datasets, including streamflow, groundwater levels and basin-scale evapotranspiration. Environmental flow alteration was quantified using the IAHRIS framework under managed and naturalised conditions. Results reveal that while annual discharge volumes remain near stable, substantial degradation occurs in low-flow magnitude, duration and seasonal structure. Groundwater abstraction-induced baseflow reduction emerged as the primary driver of low-flow collapse, particularly during the irrigation season. The proposed framework provides a transferable, process-oriented methodology for diagnosing groundwater-driven environmental flow alteration in intensively irrigated basins and offers a robust basis for evaluating sustainable groundwater–surface water management strategies under increasing water demand.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"40 7","pages":""},"PeriodicalIF":3.1,"publicationDate":"2026-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148386496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Monsoon-Driven Hydrological Pathways of Flood Generation in Semi-Arid River Basins","authors":"Roma Varghese,&nbsp;Jasti S. Chowdary,&nbsp;Chellappan Gnanaseelan","doi":"10.1002/hyp.70622","DOIUrl":"https://doi.org/10.1002/hyp.70622","url":null,"abstract":"<div>\u0000 \u0000 <p>Hydrological processes that drive basin-scale flood generation in semi-arid river systems remain poorly constrained, limiting effective basin management under an increasingly variable monsoon regime. Using a historic monsoon flood in a regulated semi-arid basin, we show that the synchronisation of hydrometeorological perturbations (or extremes) with reservoir operations activates distinct hydrological pathways responsible for extreme downstream flooding in semi-arid river basins. A systematic change in rainfall intensity distribution from light to moderate and heavy events as the monsoon progressed altered the basin-scale hydrological balance. The rainfall sequencing, from widespread early-season events to intense, localised late-season extremes, transitioned the basin from an infiltration-dominated behaviour to a runoff-dominated response. These transitions produced an atypical dual-peak reservoir discharge pattern–an unprecedented hydrological response in a semi-arid basin, where high reservoir outflows are rare and, when they occur, are confined to a single seasonal peak. Consequently, basin buffering capacity was progressively reduced during the staggered first discharge peak, promoting runoff concentration during the subsequent highly synchronised peak release. The late-season occurrence of dynamically driven mesoscale convective systems intensified this hydrological response by delivering concentrated rainfall when antecedent storage and hydrological loading were already elevated. The conceptual framework developed from the extreme monsoon event demonstrates that flood generation in regulated semi-arid basins is also governed by the spatio-temporal organisation of rainfall, antecedent hydrological pressure and the transition of reservoir systems from buffering to synchronising behaviour. These previously undocumented characteristics of the regional hydrometeorology and flood response serve as a basis for improved process-level understanding of semi-arid river basin hydrology. The findings of this study provide actionable insights for anticipatory flood management, adaptive reservoir operations and climate-resilient basin-scale planning in dryland river systems experiencing intensifying hydroclimatic extremes.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"40 7","pages":""},"PeriodicalIF":3.1,"publicationDate":"2026-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148386497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrating Geophysics and Geochemistry to Characterise Geothermal Basalt Critical Zone Evolution, Johnston Draw, Idaho","authors":"Eva Smith,&nbsp;Bradley Carr,&nbsp;Kathleen A. Lohse,&nbsp;Dario Grana","doi":"10.1002/hyp.70620","DOIUrl":"https://doi.org/10.1002/hyp.70620","url":null,"abstract":"<div>\u0000 \u0000 <p>The critical zone (CZ) evolves through coupled physical and chemical processes that drive subsurface weathering and mass loss. Quantifying these processes is commonly based on borehole geochemistry, which provides robust but spatially limited constraints, while near-surface geophysical methods offer broader coverage but are often interpreted qualitatively. In this study we integrate borehole and surface geophysical data with the bulk mass transfer coefficient (bulk <i>τ</i>) to develop Geophysical Tau (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>GT</mi>\u0000 </mrow>\u0000 <annotation>$$ mathrm{GT} $$</annotation>\u0000 </semantics></math>), a geophysics-based proxy for subsurface weathering that better constrains weathering patterns than directly converting ERT to bulk <i>τ</i>. The method is demonstrated using coincident borehole geochemical, borehole geophysical and surface resistivity datasets collected in volcanic rock in Johnston Draw, a subwatershed of the Reynolds Creek Experimental Watershed and Critical Zone Observatory, Idaho. <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>GT</mi>\u0000 </mrow>\u0000 <annotation>$$ mathrm{GT} $$</annotation>\u0000 </semantics></math> is calibrated at the borehole by linking bulk <i>τ</i> to geophysical indicators of weathering and is extended spatially using surface electrical resistivity tomography data. The resulting <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>GT</mi>\u0000 </mrow>\u0000 <annotation>$$ mathrm{GT} $$</annotation>\u0000 </semantics></math> reveals laterally extensive, clay-rich weathered zones that are not explained by meteoric infiltration alone and are consistent with interpretations of bottom-up weathering driven by convection of geothermally influenced fluids. Geophysical Tau provides a quantitative framework for integrating geochemical and geophysical observations to interpret subsurface mass loss and weathering and is transferable to analogous volcanic settings worldwide.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"40 7","pages":""},"PeriodicalIF":3.1,"publicationDate":"2026-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148386498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modelling Climate Change Effects on Groundwater Recharge and Temperature for a Pre-Alpine Lysimeter","authors":"Christian Moeck,&nbsp;Jannis Epting,&nbsp;Joaquin Jimenez-Martinez,&nbsp;Love Råman Vinnå,&nbsp;Martin Hirschi,&nbsp;Mario Schirmer,&nbsp;Raoul A. Collenteur,&nbsp;John Molson","doi":"10.1002/hyp.70602","DOIUrl":"https://doi.org/10.1002/hyp.70602","url":null,"abstract":"<p>Groundwater recharge patterns are expected to shift due to climate change; however, the impact on recharge temperature remains an open question. This study investigates the combined impact of climate change on groundwater recharge rates and temperature in a pre-alpine region of Switzerland. By applying a 1D numerical model calibrated with unique lysimeter data, daily recharge rates and temperature dynamics were simulated under 47 climate model projections for three greenhouse gas scenarios (RCP2.6, 4.5 and 8.5) from 1981 to 2099. Results project an annual increase in recharge of 7% (RCP2.6) to 20% (RCP8.5), with rates expected to increase from approximately 702 mm a⁻¹ to a maximum of 770 mm a⁻¹ (RCP2.6), 785 mm a⁻¹ (RCP4.5) and 842 mm a⁻¹ (RCP8.5) by the end of the century, driven primarily by higher winter recharge. Although low recharge rates in summer show minimal change, analysis of the drivers indicates that increased evapotranspiration and decreasing rainfall will extend the periods of low recharge rates into autumn, intensifying potential water stress during warmer months. Moreover, groundwater temperatures are projected to increase together with air temperature, increasing from 10.8°C to 11.6°C (RCP2.6), 12.2°C (RCP4.5) and 13.6°C (RCP8.5) by the end of the century, representing an increase of between 7.5% (RCP2.6) and 26% (RCP8.5). Changes in air temperature mainly drive groundwater warming, whereas changes in recharge rates have minor effects. This study highlights the need for adaptive water management to address shifting seasonal groundwater recharge rates and rising temperatures in pre-alpine regions.</p>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"40 7","pages":""},"PeriodicalIF":3.1,"publicationDate":"2026-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hyp.70602","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148324660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydroclimatic Controls on Flash Drought Development in Northeast Asia: Roles of Atmospheric Demand and Water Availability","authors":"Minsun Kang,&nbsp;Seulchan Lee,&nbsp;Daeha Kim,&nbsp;Minha Choi","doi":"10.1002/hyp.70618","DOIUrl":"https://doi.org/10.1002/hyp.70618","url":null,"abstract":"<p>As climate change accelerates the hydrological cycle, flash droughts (FDs) have emerged as a critical challenge for water, agriculture, and ecosystem management. This study analyzes FD events across Northeast Asia (NEA) from 2000 to 2024 using the Standardized Evaporative Stress Ratio (SESR)-based approach, focusing on spatial distribution, temporal evolution, and underlying mechanisms. Over 50% of FD events occurred in northeastern cold climate zones dominated by forests and croplands, and arid, barren western regions. Northeastern regions experienced shorter drought durations due to larger water holding capacity and wetter climates, while arid zones exhibited prolonged events, often exceeding 45 days. Spring FDs peaked in northeastern NEA, while summer FDs dominated western zones during August and September. Using a novel classification framework, we categorized FD events into three cases based on variations in actual evapotranspiration (AET) and potential evapotranspiration (PET): the Both-driven (Case 1), AET-driven (Case 2), and PET-driven (Case 3) cases. Case 1, the most common type, accounted for 67.4% of total events and reflected balanced declines in AET and increases in PET across all regions. Case 2 (16.9%), driven by reductions in water availability, was concentrated in arid, barren regions during late summer to autumn, where soil moisture (SM) deficits restricted AET. Case 3 (15.7%) occurred in humid, energy-limited forests and croplands in spring, triggered by elevated atmospheric demand despite SM availability. By introducing a novel classification framework, this study highlights how interactions between atmospheric demand and water availability drive FD development across diverse hydroclimatic and seasonal conditions.</p>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"40 7","pages":""},"PeriodicalIF":3.1,"publicationDate":"2026-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hyp.70618","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148324659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Water Diversion on Hydrological and Vegetation Dynamics in a Downstream Wetland Ecosystem","authors":"Tadanobu Nakayama","doi":"10.1002/hyp.70624","DOIUrl":"https://doi.org/10.1002/hyp.70624","url":null,"abstract":"<p>The Oze region in central Japan was largely spared from large-scale hydropower development; however, a small-scale water diversion scheme for electricity generation was implemented in the mid-20th century. This study applies the process-based NICE-BGC model to the Lake Ozenuma–Ozegahara Marsh basin to evaluate the long-term impacts of upstream water diversion on hydrological processes and downstream vegetation dynamics over the past 57 years. Model results indicate that alterations in lake water balance and diversion practices have significantly influenced downstream hydrology, including discharge to the Nushiri River and water level dynamics in Ozegahara Marsh. Following water diversion, lake levels exhibited increased seasonal variability and more rapid recovery during spring (April–June), leading to changes in riverine inflow to the marsh. Despite the marsh's flow-regulating capacity, simulations suggest that long-term changes in surface water and groundwater regimes have contributed to vegetation shifts, in addition to climatic influences. These effects are particularly pronounced in the eastern marsh during the earlier part of the simulation period. The results further indicate expansion of high-moor vegetation (<i>Oxycocco–Sphagnetea</i>) towards riparian zones and an increase in intermediate marsh vegetation (<i>Moliniopsietalia japonicae</i>), consistent with previously reported observations. The model captures spatially explicit relationships between hydrological change and vegetation succession across major plant communities. These findings provide a basis for assessing basin-scale hydrological alteration, identifying groundwater-dependent wetland ecosystems and informing adaptive management strategies for wetland conservation under altered hydrological regimes.</p>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"40 7","pages":""},"PeriodicalIF":3.1,"publicationDate":"2026-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hyp.70624","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148324661","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Trade-Offs in Constraining Evapotranspiration Estimates in Complex Landscapes Using a Tracer-Aided Ecohydrological Model","authors":"Hanwu Zheng,&nbsp;Doerthe Tetzlaff,&nbsp;Christian Birkel,&nbsp;Songjun Wu,&nbsp;Christian Marx,&nbsp;Tobias Goldhammer,&nbsp;Chris Soulsby","doi":"10.1002/hyp.70625","DOIUrl":"https://doi.org/10.1002/hyp.70625","url":null,"abstract":"<p>Evapotranspiration (ET) links vegetation and soils to the atmosphere and can be the dominant water flux in many areas. Whilst the estimation of ET can be constrained by different observations (e.g., discharge, stable water isotopes, remote sensing products etc.), their information content differs and their trade-offs in model calibration are usually unknown. This is particularly the case in ET-dominated, intensively managed catchments where ET strongly affects water supply and ecosystem services. Here, we investigated the heavily-managed Middle Spree catchment (MSC, ~2800 km²) in NE Germany, a sub-basin of the River Spree that includes the large Spreewald wetland (~472 km²) and serves as a key water resource for Berlin. The catchment is strongly impacted by groundwater abstraction and drainage. We applied multiple calibration schemes that combined different observations in a tracer-aided, spatially distributed catchment model (STARR) over a 20-year period, to investigate linkages between ecohydrological functioning and ET processes. Importantly, trade-offs among performance metrics were subsequently analysed in the solution space of multi-variable calibrations using Shapley additive explanation (SHAP) analysis. We found that discharge and temporal ET patterns can constrain water balance volumes, though their influence was modulated by ET-dominated wetlands and human management. In contrast, incorporating spatial ET patterns and isotopic observations led to more plausible spatial representations of hydrological processes (i.e., ET and subsurface storage). Isotopic data uniquely captured relative contributions of evaporation and transpiration to total ET (ET partitioning). However, the constraining power of these observations was limited by trade-offs, which were reflected in contrasting hydrological processes. The wetlands and human management could also influence these constraints. Although multiple calibration schemes revealed competing hypotheses of local hydrological functioning, they collectively provided richer and more integrated insights into how human management influences ecohydrological functioning in complex ET-dominated catchments.</p>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"40 7","pages":""},"PeriodicalIF":3.1,"publicationDate":"2026-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hyp.70625","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148324733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Eco-Hydrological Regime Shifts Triggered by Declining Snow To-Rainfall Ratios in Alpine Transition Zones","authors":"Yiwen Li,&nbsp;Yunhe Fang,&nbsp;Shina Wei,&nbsp;Xinrong Wang,&nbsp;Yizhen Shi,&nbsp;Rongrong Liu,&nbsp;Yun Zhang,&nbsp;Bo Wang","doi":"10.1002/hyp.70613","DOIUrl":"https://doi.org/10.1002/hyp.70613","url":null,"abstract":"<div>\u0000 \u0000 <p>Climate warming is accelerating the transition from solid to liquid precipitation in high-altitude regions, yet the physical mechanisms by which this phase shift alters intra-annual water partitioning and ecosystem availability remain poorly quantified. Using multi-decadal (2001–2020) hydro-climatic datasets and remote sensing observations across the Tibetan Plateau, we investigated the eco-hydrological dynamics within the critical 4000–5500 m elevation transition zone. We identified a sequential moisture retention mechanism where pre-monsoon snowmelt acts as a critical seasonal buffer, sustaining subsurface soil moisture and initiating spring vegetation green-up prior to the summer monsoon. However, our analysis reveals that advancing snowmelt onset is temporally decoupling this moisture supply from peak biological demand, inducing an early-season water deficit that significantly constrains vegetation growth. Crucially, we identified a hydrological equilibrium threshold at a multi-year mean snowmelt-to-rainfall (S/R) ratio of approximately 0.23, which demarcates the boundary where alpine ecosystems transition from a snow-sensitive to a rain-dominated state. This shift fundamentally diminishes the cryospheric buffering capacity due to the loss of slow-release snowpack infiltration. Furthermore, the reduction in autumn snowmelt compromises antecedent soil moisture memory—a stabilising function that rainfall fails to replicate due to increased rapid surface runoff. These findings demonstrate that declining S/R ratios inherently reduce the intra-annual reliability of seasonal water supplies, fundamentally altering the eco-hydrological stability of alpine environments.</p>\u0000 </div>","PeriodicalId":13189,"journal":{"name":"Hydrological Processes","volume":"40 7","pages":""},"PeriodicalIF":3.1,"publicationDate":"2026-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148306040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}